SoHo’s landmarked Puck Building is getting posh penthouses, The Post has learned.

The mixed-use red brick building at 295 Lafayette St. on the southeast corner of East Houston Street is getting a small rooftop addition and residential makeover of its two top floors, which have expansive views, sources said.

Owner Jared Kushner, aka Ivanka Trump’s husband and dad to their newborn, Arabella Rose, is planning as many as six elegant and energy-efficient units that will range in size from 5,000 square feet to 8,500 square feet and range in price from $15 million to $50 million. Four penthouses also will have private terraces.

“They are designing six, very customized high-end homes with great finishes, big closets and layouts planned as if they were moving in themselves,” said a source familiar with the planning. No marketing company has yet been chosen.

As part of the plans, the eighth and ninth floors will be completely redone, and a proposed partial rooftop structure must be approved by the city Landmarks Commission. The units will also have their own private lobby and entrance on Lafayette Street.

Kushner was recently spotted touring SoHo penthouses, but rather than seeking a new nest for him, Ivanka and daughter Arabella, sources said, he was actually scoping out the competition.

Kushner, who oversees the family real estate company, Kushner Cos., and is publisher of the New York Observer, could not be reached for comment.

A portion of the Puck Building’s ground and lower levels, once used to print the irreverent Puck magazine, are being renovated for a new 39,000 square-foot REI outdoor gear store set to open in November.

Other floors are leased by large and small office tenants that include New York University, the eyewear company Warby Parker, and by a venture capital firm, Thrive Capital, run by Jared’s brother Joshua.